Some linux distributions (S.u.S.E. 6.4 reported) ship with kscd (a CD player for the KDE Desktop) sgid disk. kscd uses the contents of the 'SHELL' environment variable to execute a browser. This makes it possible to obtain a sgid 'disk' shell. Using these privileges along with code provided in the exploit, it is possible to change attributes on raw disks. This in turns allows an attacker to create a root shell, thus compromising the intergrity of the machine.
Red Hat, Linux Mandrake, and Turbo Linux do not currently ship with kscd setgid 'disk'.